As others have pointed out so well, a chuck is an accessory and as such, usually optional. As with so many other things in life, there's quite often more than 1 way to do something.
OTOH, if you nonetheless are leaning toward buying a chuck, consider whether you'll also want extra jaws (perhaps later, if not right away) to make that chuck more versatile. Learn what you can about dovetailed and serrated (jaw types) holding methods as they relate to what you'll hold in the chuck's jaws, based on the types of objects you'll want to turn.
Previously recommended chucks may be every bit as good or better--I have no experience with any other in its price class--but Technatool's
Nova Precision Midi has been serving me well since I started turning. The extra jaws I've purchased for it
will also work with any of the larger Nova chucks if I ever decide/need to upsize. And for a few more days, it's available at probably the
lowest price I've seen anywhere within the last 2 years.
Using "tommy bars" to scroll the jaws instead of a T-handled "key" and turning what's sometimes described as the "wrong way" (counter clockwise) to tighten are the primary criticisms offered by some folks. When you're new and not already accustomed to a different system, my advice is weigh the convenience vs. the price, quality, upgradability, and company product and customer service reputation. As always, opinions are subject to change if an issue arises, but it seemed like a good value at the time and I can still recommend it today.
